The "D" Plane (Part #1)
The New Ball Flight Laws
The D Plane is short for Descriptive Plane.
Theodore Jorgensen author of "The Physics of Golf" discusses in his book the physics behind the collision of the clubface and the golf ball.
It discusses what occurs and how the ball takes off after separation from the clubface.
It is basically what the golf ball will do when the clubface strikes it.
He says something to the effect that two intersecting lines determine a plane.
The D Plane is formed by the line representing the direction of the club head is moving (at the time the ball separates from the club face).and the line representing a direction perpendicular to the club face (at the time the ball separates from the club face).
The BLUE LINE in the above diagram is the direction the clubhead is moving at separation (often called swing path) and the RED LINE in the diagram is the line perpendicular to the club face at separation (called club face in the diagram).
Basically this is where the (true) Clubface Angle and the (true) Swing Path are traveling creates this plane. He calls it the D Plane because of it is Description of the collision between the clubhead and the golf ball.
The D Plane shows that the initial direction the ball takes off on separation is on the D Plane and at an angle between the clubhead direction and the clubface perpendicular. Measurements using Trackman show that initial ball flight direction is close to the club face perpendicular direction (85% approximately).
The ball only curves away from the normal gravity - air resistance trajectory due to spin put on the ball during impact with the club.
When the club strikes the ball at an angle (eg lofted club) back spin will be put on the ball causing it to rise in flight. If the path is going in a different direction to the club face horizontal or side spin will be put on the ball causing it to slice or fade.
In simpler terms, the clubface has a bigger influence on the starting direction than the swing path.
The D Plane also illustrates that the initial trajectory of the ball will be slightly lower than the true effective loft of the club.
Homer Kelly also describes these effects but he does not use the simplifying concept of the D Plane explanation making his Chapter 2 rather more difficult to understand for the practical golfer.
The Old Ball Flight Laws
The Old Ball Flight Laws state that the ball will start in the direction of the club path and curve if the club face is pointed in a different direction than the clubpath.
The New Ball Flight Laws
The New The New Ball Flight Laws have been proven and are Factual. This concept first written about in “The Physics of Golf” has changed many teachers' ideas of what causes the ball to fly to way that it does
These New Ball Flight Laws have been drawn by John Graham Golf
"D" Plane Explanation Part #1 by John Graham
"D" Plane Explanation Part #2 by John Graham
Terms Used when describing The "D" Plane
Vertical Swing Plane (VSP) - is the Swing Plane Vertical to the ground (90 Degrees).
Horizontal Swing Plane (HSP) - is the swing Plane lying on the ground (0 Degrees).
Horizontal Launch Angle (HLA) - Is determined by only two parameters, the Club Path and the Clubface Angle.
Vector - has both Magnitude (Distance) and Direction
Loft - Angle of the Clubface
Angle of Attack - Vertical Launch Angle (VLA)
The following video will explain the D-Plane. This is a very important video to watch because the D-Plane explains nearly everything that happens to cause the ball to slice or hook. It is based on the "New Ball Flight Laws".
It also explains why higher lofted clubs are more difficult to draw or fade with. When you understand the D-Plane it becomes easier to determine what swing changes are needed to fix the ball flight.
D Plane Explained by Steve Bishop
Follow the Links provided for further information Regarding the D Plane
Further information can be located in our On-Line-Lesson-Course "Better Golf Stage #2". D Plane parts #2, #3, #4 have now been added and more will be included. You must register to this particular Course.
Follow the Link to our On-Line-Lesson-Course Better Golf Stage #2 for further information regarding the D Plane.